diethyl 2-(5-chloro-2-nitrophenyl)propanedioate

diethyl 2-(3-chloro-4-nitrophenyl)malonate

diethyl 2-butylsulfanylpropanedioate

diethyl 2-(morpholin-4-ylmethylidene)propanedioate

bicyclo[2.2.1]heptane-7,7-dicarboxylic acid